Antibodies, also called immunoglobulins, are proteins secreted mainly by plasma cells and are used by immune systems to identify and neutralize pathogens such as bacteria and viruses. Antibodies include IgA, IgD, IgE, IgG and IgM, wherein IgA, which can be found in breast milk, saliva, tears and bronchial mucus, is very important for mucosal immunity acting as the first line of defense against foreign pathogens. Specifically, many pathogens can infect a host by the contact with mucosal surfaces of the respiratory, intestinal and genitourinary tract, and the secretory antibody IgA, is capable of binding to multiple antigenic determinants (epitope) of pathogens so that the pathogens cannot bind to mucosal cells to infect a host.
Animal husbandry plays an important role in the agricultural production, wherein the main cause of the poor pig reproduction is related to the high mortality rate in pigs. Generally, it is believed that obligate pathogen is the main cause of diseases in pigs wherein diseases with high mortality rates constitute the majority of pigs diseases. However, according to the result of a serology investigation performed at the graduate institute of veterinary pathobiology at National Chung Hsing University, there is no apparent outbreak of obligate pathogen diseases, e.g., swine fever or pseudorabies in pigs. Some illnesses in pigs caused by infection with single type of pathogen among pathogens with relatively low pathogenicity (e.g., mycoplasma, steurella and salmonella) are not severe. However, if pigs with low immunity are primarily and secondarily infected by a complex of the pathogens with relatively low pathogenicity, the synergistic effects of illnesses would cause the pigs death. Thus, pathogens with low pathogenicity have significant impacts on pig herds with low numbers of pigs.
Colostrum is a form of milk secreted by female mammals in the first 2-3 days after giving birth, and the milk secreted after the secretion of colostrum are transitional milk and mature milk. Colostrum contains five types of immunoglobulins which are IgA, IgD, IgE, IgG and IgM, wherein the IgG content is the highest. These immunoglobulins are crucial in defending against viral infection, bacterial infection, parasites and yeasts.
However, the beneficial ingredients in colostrum are rarely isolated effectively and used except for the lactoferrin, which is purified from colostrum and utilized, and is cultivated in transgenic animals. Moreover, due to the factors such as the short time period of colostrum secretion, the unstable protein in colostrums, and the difficulty of collecting and preserving the colostrums, there are still many difficulties in the practical application of colostrum even though the benefits of colostrums are numerous.